Rotor spinning machine

ABSTRACT

The invention relates to a rotor spinning machine comprising a plurality of operating units situated next to each other, each of which contains a spinning unit ( 1 ) with a singling-out device ( 5 ) having in its body a rotatably mounted combing roller ( 52 ) equipped on its circumferential surface with an operative coating ( 521 ) around which there is provided in the body ( 51 ) of the singling-out device a circumferential fibre channel ( 511 ) whose operative section extends in the sense of rotation of the combing roller ( 52 ) from the mouth of the sliver feeding device ( 4 ) to the supply channel ( 6 ) bringing the singled-out fibres into the rotor, said circumferential fibre channel ( 511 ) having provided therein the mouth of a closable auxiliary supply channel ( 514 ) for pressure air. The closable auxiliary supply channel ( 514 ) of pressure air of each spinning unit ( 1 ) is connected to the outlet ( 531 ) of a closable means ( 53 ) related thereto whose inlet ( 532 ) is by a pressure air pipe  9 ) connected to a pressure air source ( 10 ).

TECHNICAL FIELD

[0001] The invention relates to a rotor spinning machine comprising a plurality of operating units situated next to each other, each of which contains a spinning unit with a singling-out device having in its body a rotatably mounted combing roller equipped on its circumferential surface with an operative coating around which there is provided in the body of the singling-out device a circumferential fibre channel whose operative section extends in the sense of rotation of the combing roller from the mouth of the sliver feeding device to the supply channel bringing the singled-out fibres into the rotor, said operative section of the circumferential fibre channel having provided therein the mouth of a closable supply channel for pressure air.

BACKGROUND ART

[0002] In rotor spinning machines, at each yarn interruption on each spinning unit, whether due to yarn rupture or to the tube substitution for a fully wound bobbin, the spinning process is to be restarted by inserting the yarn end into the rotor of the spinning unit where said yarn end receives fibres deposited in a well-known manner on the collection surface of the rotor whereupon the continuous spinning restarts by the following yarn draw-off. The whole cycle is called spinning-in.

[0003] Depending on the method by which underpressure is generated in the rotor, rotor spinning machines for open-end spinning can be divided into machines with active rotor fitted with vent holes for generating the underpressure in the rotor by its own revolving motion on the one side, and into machines with passive rotor in which the underpressure is generated by seating the rotor in an underpressure chamber connected with an underpressure source on the other side. While there are some mutual differences in the spinning-in operation, each of them keeps the respective combing roller in uninterrupted rotation while the sliver feed is stopped. The rotating combing roller releases fibres from the sliver end or also tears off or breaks off parts thereof, and this process goes on for a not predetermined time interval lasting up to the arrival of an attending device or of the operator. If the spinning-in operation is carried out by the attending device, whether automatically or manually, on a fibre band made of such a damaged sliver end, the piecer quality is poor and the number of failed spinning-in attempts high. Poor quality piecer reduces the yarn usefulness for further processing in the textile industry such as in weaving since it leads to ruptures of the yarn being processed or to aesthetic defects of final products.

[0004] The patent CZ 280036 G6 discloses a method of spinning-in yarn on rotor spinning machines in which the interruption of the spinning process is followed by the stop of the sliver feeding into the the singling-out device whose combing roller goes on rotating, the rotor is stopped at least for the cleaning period and then, at the restart of the rotor, the rotor receives back the yarn end which is brought into contact with the fibre band in process of formation. Before the rotor start and at the latest simultaneously with the beginning of the sliver feed, the surface of the combing roller is exposed to the action of pressure air acting in the direction of the combing roller rotation between the place of inlet of the sliver to the combing roller and the beginning of the supply channel for feeding singled-out fibres to the rotor. In this way, sliver fibres and stuck impurities are removed from the operative surface of the combing roller. The pressure air supply is then stopped and the singled-out fibres are in a well-known manner supplied into the rotor.

[0005] Said patent discloses also a device for carrying out the method for rotor spinning machines with active or passive rotor fitted with an attending device. Rotatably mounted in the body of the singling-out device of the rotor spinning machine is a combing roller around whose cylindrical surface fitted with an operative coating there is provided a circumferential fibre channel continuously followed by the supply channel for feeding singled-out fibres to the rotor. Related to the combing roller is a sliver feed device interrupting the circumferential fibre channel around the combing roller. Into this fibre transport channel is introduced the end of a closable pressure air supply channel whose inner space is closed by a back valve which is on the outer side of the body of the singling-out device adapted for connection of the pressure air supply provided on the attending device, at least the end part of the pressure air supply, serving for the connection to the back valve, being adjustably mounted on the attending device.

[0006] The drawback of this solution consists in high requirements imposed upon the precision of the stop of the attending device in front of the operating unit of the rotor spinning machine and in equally high requirements imposed on the precision of the construction and adjustment of the motion path of the pressure air supply which both are necessary to ensure that the end part always comes to sit exactly on the back valve of the operating unit to be attended. Failing this, the spinning-in either fails to take place or leads to such a poor piecer quality as to render necessary a repetition of the spinning-in process.

[0007] The invention aims to simplify the action of the attending device in restarting the spinning process on an operating unit of a rotor spinning machine while maintaining the pressure air action on the surface of the combing roller prior to the rotor start and at the latest simultaneously with the start of the sliver supply channel and the termination of the action of the pressure air stream after the removal of the damaged and shortened fibres of the sliver end away from the spinning rotor area.

PRINCIPLE OF THE INVENTION

[0008] The goal of the invention has been achieved by the rotor spinning machine according to the invention whose principle consists in that a closable auxiliary supply channel of pressure air of each spinning unit is connected to the outlet of a closable means related thereto whose inlet is by a pressure air pipe connected to the pressure air source.

[0009] This solution means a substantial modification of the attendance of the operating unit in restarting the spinning since the attending device only sends a command to the closing means to supply pressure air to the auxiliary supply channel and, as the case may be, to stop the supply. In other words, the attending device contains no means for pressure air supply and consequently needs no pressure air source. The attending device is thus considerably simplified and less expensive. At the same time, requirements imposed upon the precision of the stop position of the attending device in front of the operating unit are reduced, and conditions for shortening the attending time required for the spinning-in operation are created.

[0010] The solution is applicable also to semi-automatic rotor spinning machines in which the operator manually carries out only preparatory operations for restarting the spinning connected with the detecting and introducing the yarn end into the spinning-in preparatory position. Other spinning-in operations are carried out automatically by the means of the operating unit on the basis of the command given by the operator.

[0011] The closing means is preferably made as a valve whose control is coupled with a control unit of the operation unit of the rotor spinning machine which is in semi-automatic machine responsible for the whole automatic part of the spinning-in process incorporating due to this arrangement also the removal by air stream of damaged and shortened yarn end fibres prior to the spinning-in proper so as to ensure that such fibres do not enter the piecer. This increases the piecer quality in manually operated (attended to) semi-automatic rotor spinning machines to a level with rotor spinning machines equipped with a spinning-in attending device. In automatic machines, the attending device is rendered simpler and cheaper.

[0012] Each control unit is coupled with at least one communication means for communicating with the attending device at least in the time period when the attending device is stopped in its attending position in front of the operating unit in question. The communication means between the control unit and the attending device are preferably contactless.

[0013] For manual attendance, each control unit is connected with at least one means, made as a rule as a start push-button, for starting the spinning-in on the operating unit

[0014] To permit the tilting of the spinning unit, at least a part of the pressure air pipe is made as a pressure hose.

[0015] The pressure air source is preferably made as a compressed air pipeline situated along the machine length and thus simply ensuring pressure air distribution to all operating units of the machine.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Examples of embodiment of the device according to the invention are schematically shown in enclosed drawings in which

[0017]FIG. 1 is a view of the spinning unit in section,

[0018]FIG. 2 a section of the singling-out device and of other parts of the spinning unit, and

[0019]FIG. 3 a section of the pressure air closing means.

EXAMPLES OF EMBODIMENT OF THE INVENTION

[0020] The rotor spinning machine comprises a plurality of operating units situated next to each other. Each of them produces yarn from a textile fibre sliver and winds the yarn produced onto a bobbin.

[0021] The rotor spinning machine is made as a fully automatic or as a semi-automatic one; the invention is not applicable to spinning machines with exclusively manual control.

[0022] The fully automatic rotor spinning machine is fitted with an attending device adjustably situated along the operating units of the rotor spinning machine and fitted with means for carrying out attending operations on the operating unit when restarting the spinning and/or doffing fully wound bobbins and substituting empty tubes for them.

[0023] The semi-automatic rotor spinning machine is partly attended to manually and partly fitted with spinning-in automation means. Related to each operating unit of the semi-automatic spinning machine is a control unit, intended to control and/or to collect data and to this end connected with a sliver supply device, a yarn quality/presence monitor, a control means for releasing a yarn deflection member and letting the yarn end arrive at the collecting groove of the spinning rotor, and with control means for starting the yarn draw-off and winding. Other operations required for restarting the spinning on the operating unit are carried out manually so that during a yarn rupture the operator manually detects the yarn end on the bobbin, winds off and meters the required yarn length, cleans the spinning rotor, and leads the yarn to its preparatory spinning-in position in which the yarn rests on the deflecting means in which its end does not reach onto the collecting groove of the spinning rotor. At the end, the operator sends the command for initiating subsequent spinning-in steps.

[0024] Each operating unit comprises a spinning unit 1 and a sliver can 2 seated thereunder and containing a sliver 3 led from it to a feeding device 4 of the spinning unit 1. The feeding device 4 is followed by a singling-out device 5 having related thereto a supply channel 6 of singled-out fibres leading into a rotor 7 made in one of the well-known variants either as an active or as a passive rotor. The active rotor shown in FIG. 2 comprises vent holes serving for generating underpressure. The passive rotor is made as a full-wall open rotary body without vent holes and seated in an underpressure chamber whose underpressure generates underpressure also in the inner space of the passive rotor.

[0025] The rotor 7 produces in a well-known manner yarn 8 which is by a not shown draw-off device delivered from the rotor and by a well-known not illustrated winding device wound on a bobbin.

[0026] The singling-out device 5 comprises a body 51 of the singling-out device having seated therein a rotatably mounted combing roller 52 whose cylindrical circumferential surface is fitted with an operative coating 521. Situated opposite the circumferential surface of the combing roller 52 is the mouth of the feeding device 4 of the sliver 3. Around the operative coating 521 of the combing roller 52 there is created a circumferential fibre channel 511 whose operative section extends in the direction of rotation of the combing roller 52 from the mouth of the feeding device 4 of the sliver 3 to the supply channel 6 for feeding singled-out fibres into the rotor 7. The operative section of the circumferential fibre channel 511 is followed by an impurity removal channel 512 provided in the body 51 of the singling-out device 5 in a well-known manner in such a way that it ends in an underpressure channel 513.

[0027] In the example of embodiment of the spinning machine with the active rotor shown in FIG. 2, an auxiliary supply channel 514 made in the body 51 of the singling-out device 5 ends in the operative section of the circumferential fibre channel 511 between the mouth of the feeding device 4 and the impurity removal channel 512. The inner space of the auxiliary supply channel 514 is connected with an outlet 531 of a closing means 53 of pressure air mounted in or on the body 51 of the singling-out device 5 and made for instance as an electromagnetic valve. The closing means 53 is fitted with a control member 533 interconnected with a control unit 11. An inlet 532 of the closing means 53 is by a pressure air pipe 9 connected with a pressure air source 10 situated on the spinning machine. In the shown example of embodiment, the pressure air source is made as a pressure pipeline situated along the operating units throughout the length of the rotor spinning machine. In a double-sided rotor spinning machine, the pressure pipeline can be either common to both machine sides or a separate pressure pipeline can be used for each side. The pressure air pipe 9 is at least in a part elastic, consisting of a pressure hose 91. thus permitting the spinning unit 1 to be tilted out.

[0028] In the shown example of embodiment, the closing means 53 consists of an electromagnetic valve whose control coil is connected with the control unit 11.

[0029] The closing means 53 can consist also of a pneumatic valve whose control member is connected with the control unit 11 of the operating unit of the spinning machine.

[0030] The embodiment shown in FIG. 2 can be applied also to passive rotors seated in the underpressure chamber.

[0031] The auxiliary supply channel 514 leads into the circumferential fibre channel 511 in the form of one hole or of a plurality of small-diameter holes, or also of one nozzle or of a plurality of nozzles. The objective of this arrangement consists in obtaining the required outlet velocity of air streaming from the auxiliary supply channel 514 into the circumferential fibre channel 511. The air stream coming from the auxiliary supply channel 514 into the circumferential fibre channel 511 is directed on the operative coating 521 of the combing roller 52 in the direction of rotation of the combing roller 52, the most advantageous direction of this air stream being in the direction of a tangent or secant of the operative coating 521 of the combing roller 52.

[0032] In the embodiment of the rotor spinning machine with the passive rotor situated in the underpressure chamber, the auxiliary supply channel 514 can lead into the operative section of the circumferential fibre channel 511 in the direction of rotation of the combing roller 52 as far as behind the impurity removal channel 512, i.e. between this channel 512 and the supply channel 6 for feeding singled-out fibres into the passive rotor. The proper formation of the auxiliary supply channel 514 and its connection with the closing means 53, with the pressure air pipe 9 and with the pressure air source 10 is the same as in the preceding example of embodiment.

[0033] In the automatic rotor spinning device, the attending device 12 is fitted with not illustrated well-known means for detecting the yarn end on the bobbin, unwinding and metering the yarn end required for spinning-in. opening the spinning unit, cleaning the spinning rotor, and introducing the yarn end into the delivery tube into the preparatory spinning-in position in which the yarn end does not reach as far as into contact with the collecting groove of the spinning rotor. Before the spinning-in, the yarn is held in the means of the attending device from which it is continuously released during the spinning-in operation.

[0034] The attending device 12 and each operating unit of the rotor spinning machine are fitted with communication means 13, 14 for mutual communication at least for the control of the control member of the closing means 53, for instance of the coil of an electromagnetic valve. This communication can be carried out either via the control unit 11 of the operating unit or directly between the attending device 12 and the control member 533 of the closing means 53.

[0035] In restarting the spinning on an operating unit of the rotor spinning machine by means of the attending device 12, the attending device 12 carries out all steps required to prepare the yarn 8 and the spinning rotor 7 for spinning-in. During the closing of the spinning unit 1 and before the beginning of the rotary motion of the spinning rotor 7, the attending device 12 sends a command to open the closing means 53 of pressure air of the attended operating unit so that pressure air begins to stream into the auxiliary supply channel 514 and into the operative section of the circumferential section 511 of the singling-out device 5 and carries fibres and impurities from the surface of the combing roller 53 into the impurity removal channel 511. Following this, the attending device 12 sends a command for starting the feed of the sliver 3 so that the operative section of the circumferential fibre channel 511 receives fibres that are by the pressure air stream coming from the auxiliary supply channel 514 led away from the spinning rotor 7 into the impurity removal channel 511. After a predetermined interval during which all damaged sliver fibres are deflected away from the spinning rotor, the attending device 12 gives a command or signal to close the closing means 53 and thus stops the pressure air supply to the auxiliary supply channel 514. Due to this, the fibres situated in the operative section of the circumferential fibre channel 511 are then led into the spinning rotor 7 in whose widest section they form a fibre band, and the attending device gives a command to let the spinning-in end of the yarn 8 enter the spinning rotor 7 where the spinning-in end of the yarn 8 is joined by the fibres of said fibre band. A command coming from the attending device 12 then starts the draw-off and the winding of the yarn 8 and thus resumes the spinning process on the operating unit being attended to. The attending device 12 then moves to a next operating unit in need of attendance.

[0036] In semi-automatic rotor spinning machines, the cleaning of the spinning rotor 7 and the preparation of the yarn 8 for spinning-in is carried out manually by the operator whereupon, after closing the spinning unit 1 and inserting the spinning-in end of the yarn 8 into the delivery tube, the operator gives a command to start further spinning-in steps to be carried out by the operating unit. The command to open the closing means 53 for pressure air supply into the circumferential fibre channel 511 is given either by the operator or by the control unit 11 controlling all further means of the operating unit during the spinning-in. 

1. A rotor spinning machine comprising a plurality of operating units situated next to each other, each of which contains a spinning unit with a singling-out device having in its body a rotatably mounted combing roller equipped on its circumferential surface with an operative coating around which there is provided in the body of the singling-out device a circumferential fibre channel whose operative sections extend in the sense of rotation of the combing roller from the mouth of the sliver feeding device to the supply channel bringing the singled-out fibres into the rotor, said operative section of the circumferential fibre channel having provided therein the mouth of a closable auxiliary supply channel for pressure air, characterized by that the closable auxiliary supply channel (514) of pressure air of each spinning unit is connected to the outlet (531) of a closable means (53) related thereto whose inlet (532) is by a pressure air pipe (9) connected to a pressure air source (10).
 2. A rotor spinning machine as claimed in claim 1, characterized by that the closing means (53) is made as a valve whose control is coupled with a control unit (11).
 3. A rotor spinning machine as claimed in claim 2, characterized by that each control unit (11) is coupled with at least one communication means (13) for communicating with an attending device (12) at least in the time period when the attending device (12) is stopped in its attending position in front of the operating unit in question.
 4. A rotor spinning machine as claimed in claim 2, characterized by that each control unit (11) is coupled with at least one means for the manual start of the spinning-in of the operating unit.
 5. A rotor spinning machine as claimed in any of claims 1 to 4, characterized by that at least a part of the pressure air pipe (9) is made as a pressure hose (91).
 6. A rotor spinning machine as claimed in any of claims 1 to 2, characterized by that the pressure air source (10) is made as a compressed air pipeline situated along the machine length. 